1. Field of the Invention
The present invention relates to an improved cylinder head for a multi-cylinder, water-cooled internal combustion engine. More particularly, the present invention relates to an improved cylinder head having improved coolant flow and operating efficiency.
2. Description of the Background Art
Many different designs for internal combustion engines are known, including reciprocating engines for vehicles or the like, and water-cooled internal combustion engines which exhibit high cooling performance. In one known design for internal combustion cylinder heads, the flow of coolant is travels through two parallel coolant passages formed along a cylinder row direction (see, for example, Japanese Patent Publication No. 40218/1989 and Japanese Utility Model Publication No. 5081/1990).
In another known design for cylinder heads, a coolant outlet is formed approximately centrally in the head and extends in a cylinder row direction, with a wall extending in the cylinder row direction and dividing the inside of a water jacket into the outlet side and a main coolant passage side. In this second known design, coolant which flows in the water jacket is made to flow into the main coolant passage from both sides in the cylinder row direction to the outlet side, and the coolant then advances to the coolant outlet (see, for example, Japanese Patent Laid-Open No. 2000-87798). To make the flow of coolant uniform in this manner is helpful in equalizing the temperature throughout the cylinder head, and suppressing the occurrence of a temperature gradient in the cylinder row direction of the cylinder head.
The above-described cylinder head is generally a cast product with a complicated structure for holding a large number of dynamic valve systems, and hence, there is still a need for a novel structure which makes the flow of coolant uniform, enhances engine efficiency, and enables weight reduction.
Although the known devices have some utility for their intended purposes, there is still a need to provide a cylinder head of a water-cooled multi-cylinder internal combustion engine. In particular, there is a need for an improved cylinder head of a water-cooled multi-cylinder internal combustion engine with improved coolant flow and cylinder head efficiency, designed to solve the above-mentioned problems.